The primary objectives in the research under this contract are: to conduct studies to optimize therapeutic schedules and sequences for selected two-drug combinations in tumor-bearing animals and to obtain comparative data and evaluate the potential toxicity of combination regimens. The ultimate goal of this program is to accumulate meaningful data with which to maximize therapeutic usefulness and minimize toxicologic hazard of two-drug combinations in the treatment of human malignancies and to provide a base for the translation of animal model studies to man.